المرجع الالكتروني للمعلوماتية
المرجع الألكتروني للمعلوماتية

الرياضيات
عدد المواضيع في هذا القسم 9761 موضوعاً
تاريخ الرياضيات
الرياضيات المتقطعة
الجبر
الهندسة
المعادلات التفاضلية و التكاملية
التحليل
علماء الرياضيات

Untitled Document
أبحث عن شيء أخر المرجع الالكتروني للمعلوماتية
القيمة الغذائية للثوم Garlic
2024-11-20
العيوب الفسيولوجية التي تصيب الثوم
2024-11-20
التربة المناسبة لزراعة الثوم
2024-11-20
البنجر (الشوندر) Garden Beet (من الزراعة الى الحصاد)
2024-11-20
الصحافة العسكرية ووظائفها
2024-11-19
الصحافة العسكرية
2024-11-19

Irving John Good
1-1-2018
Distribution of Molecular Speeds
1-1-2017
ضروب المتحللة حرارياً Thermolytic Variants
9-7-2020
realization (n.)
2023-11-04
الطاقة النووية لتوليد الكهرباء
22-9-2019
metagrammar (n.)
2023-10-11

August Leopold Crelle  
  
140   02:24 مساءاً   date: 12-7-2016
Author : C J Scriba
Book or Source : Biography in Dictionary of Scientific Biography
Page and Part : ...


Read More
Date: 19-7-2016 73
Date: 21-7-2016 191
Date: 12-7-2016 137

Born: 11 March 1780 in Eichwerder (near Wriezen), Germany
Died: 6 October 1855 in Berlin, Germany


August Crelle's father was a builder who had little in the way of income to be able to give his son a good education. Crelle was therefore largely self-taught, studying civil engineering. He then secured a job as a civil engineer in the service of the Prussian Government. He worked for the Prussian Ministry of the Interior on the construction and planning of roads and the one of the first railways in Germany (completed in 1838) between Berlin and Potsdam.

Had his family had the resources, then Crelle would have studied mathematics at university. He always had a love of the subject but earning money was a necessity for him. However, he was always one to be prepared to study on his own and indeed he spent a great deal of time working on mathematics. He achieved a remarkable level of mathematics considering that he had never been formally taught, and when he was 36 years old he submitted a thesis De calculi variabilium in geometria et arte mechanica usu to the University of Heidelberg and was duly awarded a doctorate.

Crelle was certainly not a great original mathematician, but he had three qualities which made him as important for the subject as any great researcher might have been. These three qualities were firstly his great enthusiasm for the subject, secondly his organisational ability, and thirdly his ability to spot exceptional talent in young mathematicians. This last gift is described in [1] as follows:-

Crelle had a unique sensitivity to mathematical genius

and in [12] as:-

Crelle had an extraordinary intuition for judging the qualities of young talents, and for encouraging then with their research work.

He founded a journal devoted entirely to mathematics Journal für die reine und angewandte Mathematik in 1826. Although not the first such journal, it was organised quite differently from journals that existed at that time since these other journals were basically reporting meetings of Academies and Learned Societies where papers were read. Crelle was very much in control of the journal, and he acted as editor-in-chief for the first 52 volumes. He did not want an exclusive work but, as he put it in the first volume, a journal which:-

... must endeavour to offer itself to a larger public so as to first and foremost ensure its longevity and the possibility to perfect itself.

Crelle realised the importance of Abel's work and published several articles by him in this first volume, including his proof of the insolubility of the quintic equation by radicals. In fact Abel and Steiner had strongly encouraged Crelle in his founding of the journal and Steiner was also a major contributor to the first volume of Crelle's Journal.

Other young mathematicians had their first papers published in Crelle's journal, largely due to his genius in spotting the importance of their research. In addition to Abel, mathematicians such as Dirichlet, Eisenstein, Grassmann, Hesse, Jacobi, Kummer, Lobachevsky, Möbius, Plücker, von Staudt, Steiner, and Weierstrass all had their early works made famous by publication in Crelle's journal.

In 1828 Crelle left the service of the Prussian Ministry of the Interior and joined the Prussian Ministry of Education and Cultural Affairs. There he used his mathematical skills and connections, advising on policy for teaching mathematics in schools and technical colleges. He spent a spell in the summer of 1830 in France studying the teaching methods used by the French. He wrote a report on his return to Germany which praised highly the way that mathematics teaching was organised in France, but he was critical of the French having such a strong emphasis on the applications of mathematics rather than, what Crelle believed in, the importance of mathematical learning in its own right. Crelle wrote (see for example [13]):-

The real purpose of mathematics is to be the means to illuminate reason and to exercise spiritual forces.

However, he became keen to bring the model of the École Polytechnique to Germany for this was the French route to train high quality teachers.

One of the outcomes of his involvement with teaching of mathematics in schools was that he published a large number of textbooks and published multiplication tables that went through many editions.

We have mentioned above Crelle's reaction to pure and applied mathematics. His original intention when he began his Journal für die reine und angewandte Mathematik was, as the title indicates, to deal equally with both pure and applied mathematics. He changed his view of this equality of balance when he found it impossible to find applied mathematics articles of the same intellectual depth to those on pure mathematics. The solution was simple, even if it required a change in policy, and that was to have a second journal for more practical mathematics and this he moved to a second journal which he started in 1829, the Journal für die Baukunst. This journal published 30 volumes but ended its run in 1851, a few years before Crelle's death.

Crelle was elected to the Berlin Academy in 1827 with the strong support of Alexander von Humboldt. In [5] Eccarius looks at:-

... the recommendations Crelle wrote for prospective members of the Academy [and] the mathematical papers he read there, as well as the prize-problems he proposed and evaluated for the Academy ...

We should say a little about Crelle's personal character and lifestyle which also proved important in his successful ventures. Abel visited Crelle in Berlin not long before Journal für die reine und angewandte Mathematik began publication. Abel wrote to Holmboë in January 1826:-

You cannot imagine what an excellent man [Crelle] is, exactly as one should be, thoughtful and yet not horribly polite like so many people, quite honest, for that matter. I am with him on as good terms as I am with you or other very good friends.

In another letter, this time to Hansteen, Abel wrote (see for example [12]):-

There is at his place some kind of meeting where music is mainly discussed, of which unfortunately I do not understand much. I enjoy it all the same since I always meet there some young mathematicians with whom to talk. At Crelle's house there used to be a weekly meeting of mathematicians, but he had to suspend it because of a certain [Martin Ohm, the brother of Georg Ohm] with whom nobody could get along due to his terrible arrogance.


1.     C J Scriba, Biography in Dictionary of Scientific Biography (New York 1970-1990). 
http://www.encyclopedia.com/doc/1G2-2830901022.html

2.     Biography in Encyclopaedia Britannica. 
http://www.britannica.com/eb/article-9027836/August-Leopold-Crelle

Articles:

3.     K-R Biermann, Ein unbekanntes Schreiben von N H Abel an A L Crelle, Nordisk Mat. Tidskr 15 (1967), 25-32.

4.     K-R Biermann, Urteile A L Crelles über seine Autoren, J. Reine Angew. Math. 203 (1960), 216-220.

5.     W Eccarius, August Leopold Crelle und die Berliner Akademie der Wissenschaften, in Mathematical perspectives (New York-London, 1981), 37-46.

6.     W Eccarius, August Leopold Crelle als Herausgeber des Crelleschen Journals, J. Reine Angew. Math. 286/287 (1976), 5-25.

7.     W Eccarius, August Leopold Crelle als Herausgeber wissenschaftlicher Fachzeitschriften, Ann. of Sci. 33 (3) (1976), 229-261.

8.     W Eccarius, Der Techniker und Mathematiker August Leopold Crelle (1780-1855) und sein Beitrag zur Förderung und Entwicklung der Mathematik im Deutschland des 19. Jahrhunderts, NTM Schr. Geschichte Naturwiss. Tech. Medizin 12 (2) (1975), 38-49.

9.     W Eccarius, August Leopold Crelle als Förderer bedeutender Mathematiker, Jber. Deutsch. Math.-Verein. 79 (4) (1977), 137-174.

10.                        W Eccarius, Die Förderung des Mathematikers Ferdinand Minding durch August Leopold Crelle, NTM Schr. Geschichte Naturwiss. Tech. Medizin 9 (1) (1972), 25-39.

11.                        W Eccarius and A Ott, Dokumente zur Biographie von August Leopold Crelle (1780-1855), NTM Schr. Geschichte Naturwiss. Tech. Medizin 11 (1) (1974), 11-15.

12.                        J-P Friedelmeyer, August Leopold Crelle, in Mathematics in Berlin (Berlin, 1998), 27-32.

13.                        W Lorey, August Leopold Crelle zum Gedachtnis, J. für die reine und angewandte Mathematik 157 (1927), 3-11.

 

 




الجبر أحد الفروع الرئيسية في الرياضيات، حيث إن التمكن من الرياضيات يعتمد على الفهم السليم للجبر. ويستخدم المهندسون والعلماء الجبر يومياً، وتعول المشاريع التجارية والصناعية على الجبر لحل الكثير من المعضلات التي تتعرض لها. ونظراً لأهمية الجبر في الحياة العصرية فإنه يدرّس في المدارس والجامعات في جميع أنحاء العالم. ويُعجب الكثير من الدارسين للجبر بقدرته وفائدته الكبيرتين، إذ باستخدام الجبر يمكن للمرء أن يحل كثيرًا من المسائل التي يتعذر حلها باستخدام الحساب فقط.وجاء اسمه من كتاب عالم الرياضيات والفلك والرحالة محمد بن موسى الخورازمي.


يعتبر علم المثلثات Trigonometry علماً عربياً ، فرياضيو العرب فضلوا علم المثلثات عن علم الفلك كأنهما علمين متداخلين ، ونظموه تنظيماً فيه لكثير من الدقة ، وقد كان اليونان يستعملون وتر CORDE ضعف القوسي قياس الزوايا ، فاستعاض رياضيو العرب عن الوتر بالجيب SINUS فأنت هذه الاستعاضة إلى تسهيل كثير من الاعمال الرياضية.

تعتبر المعادلات التفاضلية خير وسيلة لوصف معظم المـسائل الهندسـية والرياضـية والعلمية على حد سواء، إذ يتضح ذلك جليا في وصف عمليات انتقال الحرارة، جريان الموائـع، الحركة الموجية، الدوائر الإلكترونية فضلاً عن استخدامها في مسائل الهياكل الإنشائية والوصف الرياضي للتفاعلات الكيميائية.
ففي في الرياضيات, يطلق اسم المعادلات التفاضلية على المعادلات التي تحوي مشتقات و تفاضلات لبعض الدوال الرياضية و تظهر فيها بشكل متغيرات المعادلة . و يكون الهدف من حل هذه المعادلات هو إيجاد هذه الدوال الرياضية التي تحقق مشتقات هذه المعادلات.